4 A Catalogue of Models

In this chapter, we will attempt to categorise the very many analogue models researchers have
investigated. Perhaps the most basic subdivision is into classical models and quantum models, but
even then many other levels of refinement are possible. Consider for instance the following
list:

Classical models:

Classical sound.

Water waves (gravity waves).

Classical refractive index.

Normal modes.

Quantum models:

Bose-Einstein condensates (BECs).

The Heliocentric universe.
(Helium as an exemplar for just about anything.)